Pressure gas generator



Aug. 18, 1942- J. E. JOHANSSON PRESSURE GAS GENERATOR W Filed March 25,1940 nl i In aeni'or: Johan Ez c'it Ibiza Ewan, WQQJSIKVQ A-Z'C yc.

I NW

Patented 18, 1942 Johan Erik Johansson, Goteborg, Sweden,

or to Aktiebolaget Giitaverken,

assign- Goteborg.

Sweden, a corporation of Sweden Application March 25, 1940, Serial No.325,898

In Sweden March 31, 1939 6 Claims.

The present invention relates to improvements in pressure gas generatorscomprising internal combustion engines and air compressors driventhereby. In such pressure gas generators the compressed air produced bysaid compressors and the partly expanded exhaust gases of the internalcombustion engines form the pressure gas. Now, as a result of the aircompression in known generators of this type it sometimes happens, thatthe compressed air produced by the compressors reaches a temperature,which is so high that oil, which may gather at the air inlet openings ofthecylinders of the internal combustion engines or at other points, isignited, when it comes into contact with the hot compressed air. Inorder to avoid the danger and disadvantages connected with thiscircumstance it has been proposed to cool down the entire air quantityproduced by the compressors before said air is admitted to the cylindersof the internal combustion engines, which, however, results in aconsiderable reduction of the thermodynamic efliciency of the airproduction.

One object of the invention is to increase this efllciency.

Another object of the invention is to combine the compressors andinternal combustion engines of a pressure gas generatorof theabovementioned type so as to form a more concentrated and convenientconstruction.

A further object of the invention is to provide means for equalizing thetemperature of the compressed air admitted to'the internal combustioncylinders.

With these and other objects in view I provide means for intermediatecooling of a stepwise compressed portion of the air produced by thecompressors. Further features of the invention are set forth in thefollowing specification and claims.

In the accompanying drawing one embodiment of the invention isillustrated by way of example.

Fig. 1 is a side sectional view of a pressure gas generator according tothe invention.

Fig. 2 is a cross section on line II-II in'Fig. 1.

Fig. 3 is a cross section on 1ineIIIIII in Fig. 1, and x Fig. 4 is asection on line IV-IV in Fig. 1.

In the drawing l designates the lower half and 2 the upper half of acrank case of a pressure gas generator comprising an internal combustionengine and air compressors driven thereby. The internal combustionengine may naturally be of any type operating on the two or multiplestroke principle and having any number of cylinders,

pistons l3 and I 4, respectively,

and in the present embodiment of the invention a two stroke Dieselengine is illustrated comprising two Diesel cylinders 3, inwhich opposedmotion pistons 4 ahd 5 are provided. The air compressors driven by theinternal combustion engines may also be of any suitable type such asreciprocating compressors, rotating compressors or the like, at leastone of which is working with stepwise compression. The drawing shows twoone step and one two step reciprocating compressors. The pistons 4 ofthe Diesel engine are connected or preferably integral with compressorpistons 8 operating in compressor. cylinders l of single acting one stepcompressors arranged on top of the internal com bustion cylinders 3..The pistons 4 and 5 are connected by means of connecting rods 8 and 9,respectively, to a crank shaft l0 mounted in the crank case I. A furtherconnecting rod II is connected to the crank shaft I0 and by means 'of apiston rod [2 with two pistons l3 and ll of a two step double actingreciprocating compressor. In the present case said two step compressorproduces approximately one third of the total air quantity delivered bythe air compressors comprised in the pressure gas generator. The twostep compressor consists in a large cylinder I5 and a small cylinder I6, in which the operate. The cylinder I5 is provided with automaticinlet valves l1 and automatic outlet valves l8 and anoutlet chamber I 9common for both ends of the low pressure compression cylinder andserving to conduct the air compressed in the cylinder l5 to anintermediate cooler 20, which may be of any suitable type and in theillustrated embodiment is a tubular cooler, to which cooling medium issupplied through a connection 2| and from which the cooling medium isled away through an outlet 22. From the cooler 20 the air flows to aninlet chamber 23 common for both ends of the high pressure cylinder 16.cylinder I6 is provided with automatic inlet valves 24 and automaticoutlet valves 25 and an outlet chamber 28 common for both ends of thehigh pressure cylinder I 6. The air, which has been cooled down to aconsiderable extent in the intermediate cooler 20, is compressed in thecylinder I 6 to about the same pressure as the air compressed by thecompressor pistons 6 in the cylinders 1, for instance, 4 to 5 kg./cm.above atmospheric pressure. The compressed air from the two stepcompressor flows from the outlet chamber 26 through a conduit 21, whichis also connected with outlet chambers 28 of the The high pressure onestep compressor cylinders I. 29 designates the inlet chambers of thecompressor cylinders TI and 30 and 3| automatic inlet valves andautomatic outlet valves, respectively, or the compressor cylinders "I.The air produced by the one step compressors I is mixed in the conduit21 with the air produced by the two step compressor'15, it, which haspreviously been cooled down in the intermediate cooler 20 andconsequently has a lower temperature than the air produced in the onestep compressor cylinders I.

In order that the mixture or the diflerent air quantities shall obtain auniform temperature before the air reaches the internal combustioncylinders 3 a device 32 for equalizing the temperature of the compressedair is connected between the conduit 21 and a conduit 33, which isconnected to the inlet openings 34 o! the internal combustion cylinders3. The temperature equalizing device 32 consists in a sheet metal drumenclosing a pack of corrugated sheet metal 35 or other suitable heatexchange bodies with large heat exchange surfaces and preferably goodheat conductivity. The air, which has the highest temperature, gives oflheat to the heat exchange bodies upon passage of the temperatureequalizing device and said bodies give oil heat to the cooler portionsof the air passing the device so that the air, which leaves thetemperature equalizing device, is of substantially a medium temperaturecorresponding to the temperatures and quantities of compressed airproduced by the compressors 1 and l5, IS.

The compressed air produced by the compressor serves as charging andscavenging air for the internal combustion cylinders and is mixed withthe partly expanded exhaust gases, which are expelled from the motorcylinders at substantially the same pressure as the pressure of thecompressed air through outlet openings 36 and a conduit 31, which is thedelivery conduit oi the pressure gas generator. Fuel is supplied to theinternal combustion cylinders by fuel pumps 33 driven from the crankshaft ill by means of a chain drive 39 and connected with conventionalfuel injection valves 40 through pipes ll. The output of the internalcombustion engine comprised in the illustrated pressure gas generatormay be .completely utilized for driving the compressors comprised in thegenerator or a portion of the output of the internal combustion enginemay be utilized for other purposes.

It is understood that my invention is by no means limited to theembodiment above described and illustrated in the drawing, which shouldonly be considered as an example, and the invention may naturally bemodified in several different ways within the scope of the followingclaims. The pressure gas generator may naturally be of a type, in whicha portion of the compressed air does not pass the motor cylinders but isadmixed to the exhaust gases of the motor when said gases are alreadyexpelled from the motor. In such a generator :3, direct communicationmay be provided between the delivery conduit of one or all compressorsand the delivery conduit of the generator and suitable valves may beprovided in said conduits to ensure the desired operation. Thus, asshown in Figures 1 and 2, a passage or conduit 50 is arranged tocommunicate the conduit 33 with the conduit 31. A casing 5| on the pipeor passage 53 houses a valve (not shown), and a handle 52 is connectedto the? valve for controlling the flow of the air throug the passage 53.

What I claim is: 1. In a pressure gas generator, an internal combustionengine, an air compressor without inter-stage cooling driven bysaidinternal combustion engine, a multi-stage air compressor driven by theinternal combustion engine, a common delivery conduit for saidcompressors communicating with the combustion. cylinders oi the internalcombustion engine, and an interstage cooler between. two steps in saidmultistage compressor, the compressed air from said compressors and thepartly expanded exhaust gases of the internal combustion engine formingtogether the pressure gas produced by said pressure gas generator.

2. In a pressuregas generator, a reciprocating,

'duced by said generator.

3. In a pressure gas generator, a reciprocating internal combustionengine, opposed motion pistons in said internal combustion engine, acrank shaft, connecting rods connecting said crank shaft and saidopposed pistons, a two step reciprocating air compressor operated bymeans of a connecting rod connected. to said combustion engine, aircompressors driven by said internal combustion engine, at least one ofsaid air compressors having means for stepwise compression of the airpassing through said compressor, a communication between two steps ofsaid stepwise compressor, a cooling means provided in said communicationand adapted for intermediate cooling of the air passing said stepwisecompressor, said stepwise comm'essor being arranged to produce about onethird of the compressed air produced by all comnressors of saidgenerator, and a common delivery conduit for said compressorscommunicating with the combustion cylinders of the internal combustionengine, the compressed air of said compressors and the exhaust gases ofthe internal combustion engine forming together t e pressure gasproduced by the generator.

5. In a pressure gas generator, an internal c mbustion engine. aircompressors driven by said internal combustion engine, at least one ofsaid compressors'having means for stepwise compression of the airpassing through said compressor, a communication between two steps ofsaid stepwise compressor, a cooling means in said communication adaptedfor intermediate cooling. of the air passingthrough said communication,a delivery conduit communicating with said compressors and the internalcombustion cylinders, and a temperature equalizing desaid internalcombustion engine, at least one of said air compressors having beans forstepwise compression of the air passing through said compressor, acommunication between two steps of said stepwise compressor, a coolingmeans in said communication adapted for intermediate cooling of the airpassing through said communication, aconduit communicating with the aircompressors and the internal combustion cylinders, a temperatureequalizing device in said conduit between the compressors and theinternal combustion cylinders, and heat exchange bodies in said device,the compressed air of said compressors and the exhaust gases of theinternal combustion engine forming together the pressure gas produced bysaid generator.

J OHAN ERIK J OHANSSON.

